This invention relates to a method and means for thermally protecting objects from cold temperatures. This invention particularly relates to a method of protecting objects from cold temperatures by utilizing an aqueous cover around said objects.
British Pat. No. 1,144,366 teaches a method for the protective covering of plants by interposing an aqueous layer between the area to be protected and the sky.
While the concept taught in the British Patent sets forth many advantages of utilizing water or water mixtures as thermal protective coverings, there are certain novel improvements which are the subject matter of the present invention.
When water is deployed as a relatively air tight covering over a space to be protected, cold weather cannot freeze anything in that space until it first freezes the protective cover of water. The freezing of this water is slow because water liberates heat on freezing, about 80 calories of heat per gram of ice formed. This release of heat is comparable to the release of an equal weight of rock cooling from about 500.degree. Farenheit down to about 32.degree. Farenheit. In contrast to the hot rock, water releases its heat at 32.degree. Farenheit as if it were a water burning furnace thermostated at 32.degree.. Since heat loss from the system is proportional to the difference between the inside and outside temperature this low temperature release of heat is far more effective than would be a hot rock under a hot cap.
The above-mentioned British Patent is limited to the protection of plants by interposing between the plant and the sky a layer of water in translucent containers. In all cases a multiplicity of containers are used. The primary application of the British Patent is the covering of plants growing in a depression for an extended period of time. The patent purportedly proposes to cover single plants by utilizing a light admitting cover over a plant with water bags leaning on the cover thus covering the plant. The bags of water, if they are pliable enough to come together and seal out cold air, flow downhill and form a series of contained puddles alongside the light admitting the protective cover.
There is much need for protection of seedlings and young plants against late frosts in the Spring to enable an early start of vegetables and other seedlings. A plant which has a month's head start has an additional month at the end of the season when full development of the plant results in a maximal rate of food production. Buildings such as greenhouses, storage sheds, pits and similar structures wherein perishable material is stored or grown are susceptible to cold. Items contained in such storage structures often require elaborate heating and ventilation systems.